Purchasing the right compressor for your application is very important. Making the wrong decisions during the buying process will cause much frustration and downtime later on. There are many sources available, most of which are from compressor manufacturers, and this printed material can help you to educate yourself. Installing the compressor, air lines and compressor accessories should be the last part of the process.

There are three basic types of air compressors. These are rotary screw, centrifugal and reciprocating. Each type also has different styles, including water and air cooled, single stage or multistage, and oil flooded or oil free air. Perusing the literature provided by the manufacturers of compressors will help you to gain a good understanding of how each type works, and is necessary in order to make the right selection for your business. All of them perform the same end function, which is to compress air to a higher pressure, but their methods of accomplishing this differ significantly. These differences help them adapt to different working environments and applications.

Reciprocating compressors are possibly the simplest to understand. Put simply, the compressor takes in a specific volume of air and uses a piston to force the volume of air into a smaller volume. Reciprocating compressors have a range of 1 horsepower to over 600 horsepower. Most reciprocating compressors are oil-flooded, or lubricated. The problem with this is that a separator is needed somewhere in the air line because oil tends to work its way into the air during the pressurizing process.

This type can be purchased directly from the compressor manufacturers and are normally chosen because they are very low cost. Rotary screw compressors work on the same concept as reciprocating compressors, although it uses a rotor, not a piston. A downstream separator must be used on the rotary screw air compressor as well, and again, this type is low cost, yet the maintenance costs can be rather high.

The other type of compressor is a centrifugal compressor. The centrifugal compressor does the same job as the other types, but instead of squeezing the air into a smaller volume, the centrifugal compressor increases the air pressure by increasing the air velocity. This is an oil free air compressor, and is air cooled. As it is oil free, it also does not require a separator. The centrifugal air compressor system is used by hospitals and other applications where air must be uncontaminated. They are favored for their ability to run for long periods of time before maintenance must be performed. If, after reviewing the materials provided, with regard to the applications of use, there are still questions, it is best to consult with the compressor manufacturers.